Process of distilling oil



June 3, 1.931).` E. Psw, Jl

PROCESS oF DISTILLING on..

rma Jan. 8, 192Vv s sheets-'sheet 1 June 3, 1930.

A. E. PEW, JR

1,761,153 PROCESS 0F DISTILLING OIL Filed Jan. 8, 1927 6 Sheets-Sheet 2ron/ERS 20 Co'oL Ef? T0 V UUM 35' 36 MAW Wfcf/rf/P June 3, 1930. A. E.PEw. JR

PROCESS OF DISTILLING OIL Filed Jn. 8, 1927 6 Sheets-Sheet June 3, 1930.A. E. PEw, JR

` PROCESS OF DISTILLING OIL Filed Jan. 8, 1927 6 Sh-eefs- Sheet 5 may NQmm.

vw MN 'IY M.. l Mm W Wffm,

' June 3, 1930.

A. E. PEW, JR

PROCESS OF DISTILLING OIL Filed Jan. 8, 1927 6 Sheebs-SheeiI PatentedJune 3,y 1930 UNITED STATES PATENT OFFICE 1 ARTHUR E. PEW, JR., OF BRYNMAWR, PENNSYLVANIA, ASSIGNOR TO SUN OIL COM" PANY, OF PHILADELPHIA,PENNSYLVANIA, A CORPORATION OF NEW JERSEY PROCESS OF DISTILLING' OILApplication led January 8, 1927. Serial No. 159,754.

vIn the distillation of lubricating oil, it is necessary to heat the oilto be distilled to a temperature so high that it is partlydecomposed,`thereby producing distillates containing decompositionproducts that require expensive purification treatment to remove; andtheir complete removal can never be effected. It is, of course, wellunderstood that by distilling oil under a partial vacuum, thedistillation temperatures of the fractions to be distilled arematerially reduced, thereby enabling the distillation to be effected atlower temperatures and hence With less decomposition. It is also Wellunderstood that as an absolute vacuum is approached the boiling pointsdrop at a rate that rapidly and progressively increases, so that, if itWere possible to reasonably closely approach an absolute vacuum, theboiling points of all except the heaviest fractions could be reduced tobelow the temperature at which any substantial amount of decompositionoccurs. In distilling the high boiling point fractions, the highestvacuum that it is practicable, With modern engineering methods, tosecure, is desirable. `With a maximum racticable vacuum, it would bepossible, i local overheating could be avoided, to distill crude oilpractically down to asphalt or coke at such relatively low temperaturesas toV produce abnormally heavy and viscous lubricants that Wouldcontain so small a proportion of cracked products that they could besaid to be almostffree therefrom and would require no subsequentexpensive purification treatment. y

Known high Vacuum distillation processes (so-called) do not, however,afford the conditions required to avoid the formation of de compositionproducts, and in som/e, if not all, cases. do not even succeed insecuring the high vacuum that they are supposed to secure. Thus. inbatch distillation, the absolute pressure above the body of oil might bean absolute vacuum. and lvet the oil would actually vaporize at anabsolute pressure substantially in excess of the minimum degree ofvacuum which 1t 1s sought to obtain; for the reasonthat the hydrostaticpressuretoward the bottonivk of the column, Where vapor globules beginto form, is such that the vapor as it forms isin fact subject to anabsolute pressure sub;`

tion products as are produced at that temper-y ature by cracking orotherwise.

It has also been roposed to run oil through a longv tube in a liquidstream Whose volume is much less than that of the tube, to heat the tubein the usual Way by hot furnace gases, and to convey, through the tube,the vapors, formed during the passage of the oil through the tube, to afractional condensing apparatus, whereby distillates of different cutsmay be obtained. In this process, the vapors are not only forced totravel through the tube for a considerable distance in contact With thefiowing oil, but suc-h vapors, While they are in the tube, are subjectto the heat 0f the heating medium (which, Without an opparatus of unduesize, owing to the low heat conductivity of hot gases, must be severalhundred degrees higher than is necessary to produce. the vapors), thussubjecting the oil vapors, as Well as the liquid oil, to localoverheating. In fact, the conditions required to avoid local overheatingof the/foil and crackf ing of oil vapors are not avoided at all,regardless of the degree of vacuum that may be obtained Within thetubes. Moreover, in such process. the vapor is compelled toy travel foralong distance through the tube to the outlet thereof. lVith a tube ofreasonable diameter. it is impossible, in such an elongated stream ofvapor, to avoid a substantialy pressure drop from a point distant fromthe vapor exit to the vapor exit; and even though a condition of highvacuum may exist at the outlet end ofthe tube. the absolute pressure atpoints more. or less distant from such outlet is substantially abovethat Which it is sought to obtain and which it/ is necessary to obtainin order to satisfactorily distil the, highest boiling point products:

I having succeeded in providing all the conditions required tosuccessfully practice a high'vacuum process and have succeeded inconverting the entire body of oil, except a small percentage of residualcoke, into lubricants that require no subsequent expensive purification,and some of which possess characteristics heretofore wholly unknown.

The result obtained, however, is not due wholly to the perfection of thelubricating oil distillation process. Even when all the conditionsrequired to successfully practice a. high vacuum process are provided,it does not sufiice to produce lubricating distillates free of crackedand oxidation products and Without objectionable odor, and free fromtendency to color deterioration. The finished distillates still containcertain of these impurities because of the content of odor-producing andcolor-deteriorating products in the crude oil or because of the breakingdown of sulfur compounds incidental to the most perfect methodaofpreparing lubricating oil stock from the crude oil. Other cracked andoxidation products, as well as the impurities specified, are alsocertainly produced in ordinary processes of topping and otherwisetreating crude oil for the production of lubricating oil stock and are,in fact, produced by all such processes known to me. Among the factorsthat tend to the production of an imperfect lubricating stock may bementioned high or prolonged temperature conditions, access ofatmospheric air, and imperfect methods of adding acid neutralizingsolutions including imperfect subsequent dehydration. A

I have succeeded, not only in perfecting the lubricating oildistillation process per se, but also in providing all the conditionsrequired to produce a lubricating oil stock substantially free of allimpurities except certain odor-producing and color-deterioratingproducts, of which at least some are believed to be present in thecrude. These inevitable impurities, however, I have suceeded ineliminating from the finished disillates Without the use of any knownseparate and relatively expensive purification process but by anautomatically acting deodorizing process part-ly merged with and partlysupplemental to the distillation process.

The principal conditions whereby I secure the results sought may beenumerated as follows:A

(1) The separation of the lubricating oil stock from the crude oil by soconfining the oil against access of oxygen, by subjecting the oil, inthe necessary distilling operations, to such conditions of limitedtemperature and pressure as to avoid or minimize cracking, and by soadding an acid neutralizing solution with subsequent eectivedehydration,

as to produce a lubricating oil stock substantially free of allimpurities except certain odor-producing products.

(2) The maintenance above the lubricating oil stock, while it is beingheated (except in the distillation of relatively low boiling fractions)of a vacuum of not lower than substantially twenty-nine inches, that is,an absolute pressure not higher than twenty-five millimeters mercury. Itis preferred, however, to reduce the absolute pressure to as nearly anabsolute vacuum asis practicable, particularly in distilling the higherboiling fractions. It is practicable. to secure a substantially highervacuum than that specied.

(3) The avoidance of a column of oil of any substantial height, therebymaking the factor of hydrostatic pressure negligible.

(4:) The maintenance of the smallest practicable temperature differencebetween the' oil and the heating medium, in the distillation of thehigher boiling lubricating fractions, so as to avoid local overheating.

(5) The application of heat, principally if not wholly, to only theliquid oil, and the avoidance of conditions whereby the vapors whenformed continue to be subject to the temperature conditions required toform them; or, in other words, the maintenance of conditions under whichthe vapors tend to cool from the moment they leave the surface of theoil body.

(6) The avoidance of prolonged contact between the liquid oil beingheated and the vapors that have escaped therefrom, which is accomplishedby immediately withdrawing them from the locus of vaporization to alocus of condensation. 4 l

(7) The subsequent deodorization of the condensed oil.

The entire process, including the preparation of t-he lubricating oilstock from the crude oil, is a unitary process, in that every essentialstep contributes to the production of the ultimate pure product sought.The preparatory steps of my process preferentially involve the toppingof the crude to recover the lighter hydrocarbons, principally gasoline,at a non-cracking temperature; the addition, as known in the art, ofcaustic soda or other suitable equivalent to neutralize certain organiccompounds contained in the crude oil or produced in the subsequentdistillation process; the evaporation of the water introduced with thesoda; and the evaporationof other hydrocarbons, principally` gas oil,which are heavier than gasoline and lighter than the lubricatingfractions. rlhese operations are so conducted that the residual oil isin ideal condition for distillation into lubricating oils, beingnsubstantially or entirely yfree from products of oxidation and cracklng.

An apparatus suitable for carrying out my improved process is shown inthe drawings, in which- Fig. 1 is ay diagram, in side elevation, of apart of a complete lubricating oil distillation plant.

Fig. 2 is an end elevation of the same.

Fig. 3 is a diagrammatic View of the oil heating apparatus,

Fig. 4 is an elevational view of one of the units of the condensing,refluxing and deodorizing apparatus.

Figs. 5A and 5B represent a diagrammatic view of the part of thel plantwherein the crude oil is distilled to prepare distillates for use aslubricating stock.

I shall first describe my preferred process of treating the crude oil toprepare the oil for my process of distilling the lubricating fractions,as conducted in the apparatus shown in Figs. 5A and 5B.

Crude oil is pumped through pump 61 and line 62 through the tubes inreflux condenser 63. Here the crude is raised in temperature about 20 F.by heat exchange with the vapors from tower 78. The rise intemperaturewill Vary with the grade of crude and the amount of vapors coming offthe towers. The heated crude, continuing its passage through line 62,goes to reflux condenser 64, where it is heated to (say) 140 F. by heatexchange with the vapors from tower 90. The ycrude then passes throughheat exchanger 65, where it is in heat exchange relationship' withresidual oil, as hereafter described. Leaving this heat exchanger at atemperature of (say) 310 F., the crude then passes to a baffle tank 67held under a pressure of (say) 100 pounds gauge. This tank is of such asize that the oil 'fiows through at a velocity preferably not exceedingabout 25 ft. per hour. At this velocity, and at the last mentionedtemperature and pressure, the salt water containedin the crude, whichmay amount to about two per-cent., or over, settles to the bottom of thetank, where it is drawn off through draw-oli' pipes 68. By removing thesalt Water, subsequent troubles due to salt r deposit are eliminated,thus greatly simplifying the problem of continuously running the processwith avoidance of frequent shutdowns for cleaning the tubes of the pipestills. The removal of the salt also enables a better grade of asphalt(if the crude has an asphalt base) to be obtained at a final stage ofthe lubricating oil distillation process; such asphalt having superiorsolubility tests, i. e., containing a relatively small percentage ofinsoluble material.

The oil from tank 67 vflows through the tubes 70 and 71 of a pipe stilland thence into a vaporizer 75 at a temperature of (say) approximately450 F. This ipe still may be of conventional design, uel oil beingburned through burner 137 in-fspace 72, the products of combustionpassing upwards over tubes 70, down over tubes 71, into flue 73, andthence up stack 7 4. In order to keep the gas temperature low in thisfurnace, the

exhaust gases from :pipe still 84-85 pass through flue 100 into the firebox 72 and are mixed with the products of combustion from burner 137.This results in great economy of operation, as it enables the hottergases from pipe still 84-85 to give up their heat in pipe still 70-71.The flue gas tempera ture in Hue 73 is not above about 400 F.

The pressure in vaporizer 75 being substantially atmospheric, vapors arefreed from the incoming oil as it travels down over the inclined pans.These vapors pass upwards through manifold 76, distributor section 77and packed section 78, and out vapor line 79 into reflux condenser 63.In the latter, the vapors are condensed, the condensate being returnedthrough line 80 to the tower, or through line 81 to storage, in suchproportions as the operation of the tower requires; v

an increased amount being returned through line 80 when a lighterproduct through line 81 is desired and a decreased amount when a heavierproduct is desired. The reflux from section 78 is caught in section 77and passes through vline 91 to storage. The product through line 8l islight gasoline and the product through line 91 is an intermediategasoline.

The residual or partially topped oil, which may be said to be a lightmazout, leaving the bottom of vaporizer 75 passes through pump 82 andthe tubes 84 and 85, wherein it is heated to approximately 590 F. Atthis temperature, it passes into vaporizing tower 88, which contains apacked section and operates in a manner similar to vaporizer 75. Theproduct-'from this vaporizer that leaves through line 93 is light gasoil, and that which escapes through line 92 is heavy gas oil.

The residual oil leaving the bottom of tower 88, which may be said to bean intermediate mazout, passes through pump 96 at a temperature of (say)580 F. and through a heat exchanger 66, in which it is cooled to (say)500 F. The mazout at this temperature then goes through heat exchanger65, where it exchanges heat with crude oil as previously described. Themazout leaves this exchanger at about 360 F. and then goes throughexchanger 66, wherein it is heated to about 480 F.

By this arrangement o f exchangers, the

. mazout passes through line 99 and into tank 103 or tank 104, in whichtank it is mixed with approximately one per cent of 380 B. soda. Thesoda is pumped into the tanks through line 107 and is therein thoroughlymixed with the oil by circulation through pumps 108 and 109. Theprovision of two tanks arranged as shown affords a convenient means ofavoiding a break in the continuity of the process. The oil from line 99is run (say)-into tank 103 until it is practically full, all the air inthis tank haing been expelled by steam. The soda is then admittedthrough line 107. A pressure of (say) 360 pounds gauge is immediatelygenerated, due to the vapor pressure of the water in the4 soda at thistemperature. Pump 108 is then started and the mixture of oil and sodacirculated through line 105 back to the tank and through line 105 again.This operation should be continued for about ten minutes, or such otherand usually longer time as may be required to give an intimate mixtureof soda and oil and to enable the soda to neutralize any acidity thatmay be in the oil. As an excess amount of soda is preferentially used,the mixture will be alkaline. y

Having thus obtained the mixture, the valve on line 105 is sluit andtl1e-mixture is pumped through line 110 to tower 111. The time ofpumping out tank 103 is so arranged that the same time interval willenable a fresh charge to he treated in tank 104. Thereby a continuousfeed may be obtained in line 110.

The mixture of soda and oil under pressure goes through line 110 tovaporizing tower 111, which is maintained at a substantiallyreduced-preferably atmospheric-pressure. D ue to this reduction inpressure, enough specific heat is converted into latent heat to permitall the water which is in the soda that.

will boil at a temperature ot 460C F. to he vaporized. lt is desirable.to removel this water to as great a degree as possible to enable aygreater vacuum to be obtained in the subsequent distillation of thelubricating fractions. This object tower 111 success full)1accomplishes.

It is diiticult to get an intimate mixture between the oil and the sodawhen only a small proportion of the latter is added. However, in myprocess, I secure the advantage of a larger amount of liquid causticsoda, as it is mixed, in tanks 103 and 104, under such conditions ofpressure and temperature that thewater will not vaporize. Then, in tower111, the water which would be highly objectionable at a later stage ofthe process is removed.

The steam generated in tower 111 passes upwards through manifolds 112into condenser 113. The mazout and soda mixture passes out through line114 and pump 115 through back-pressure valve 140 into tank 116, wherethe oil is iowed over vaporizing pans. This tank is maintained under asubstantial vacuum, say of 28 inches. Due to the reduction in pressurefrom atmospheric, or about 15 pounds absolute, to about two poundsabsolute, enough sensible heat is converted into latent heat to enableall the gas oil left in the mazout from the topping process to bevaporized and pass out through line 118 into tower 119.

Due to the great velocities at Which vapors form and leave the surfaceof the oil in the Vaporizing pans of tank 116, some entrainment ofheavier oil may occur. The reflux condenser 120 at the top ,of tower 119permits, by temperature control, the lighter products to pass outthrough line 121 and throws the heavy products back down into trap 124,from which, shouldthe entrainment be particularly objectionable, theheavier products flow back to the vaporizer; or, should the entrainmentnot be objectionable, such heavier products flow into a cooler 123,where they mix with the overhead distillate flowing through line 121,condenser 122 and cooler 123 into receiving tank 125. A vacuum ismaintained on this tank by means of vacuum equipment 127. The oil ispumped from tank 125,by mean-s of pump 126.

The o il leaving tank 116 through line 117 is now in condition to besubjected to fractional distillation for the production of lubricatingdistillates and high grade asphalt.

Referring now more particularly to Figs. l, 2 and 3, the oil trom pipe117 enters the vaporizing chamber y/ of the first (1l.) of a series ofvaporizers wherein the lightest fraction of the oil is vaporized. Theresidue flows out through a pipe b into -the next vaporizer 12 of theseries wherein another, and somewhat heavier, traction is vaporized. Theresidue. then tlows out through a pipe 0 into the next vaporizer 13 ot"the series, wherein another, and still heavier fraction is vaporizcd.There may be as many vaporizers, 1l, 12, 13. l-l, etc., as may bedesired. It is preferable to provide as many vaporizers as there aredistillates to be produced; but the vapors from a single still maj1 besubjected to fractional condensation: or the vapors from dilierent partsof the same still may be separately condensed.

The `final.'residue-,ilows out "through piped into-.av-'tankg erf which`mayibe co'nnectedfto` a vacuumpumpf'through a `pipe f.

. Theheating mediumthat I employ is mer'-l 5,:c11ry1vapo'r,^or -anyvaporizable metal, metallic 'co1npound','or other substance, such aspossibly diphenyloxide, benzo phenone, sulfur, or :some-possible'Ametalaalloy, that `may beV found ito possess those characteristics ofmjme-rcury vapor that `ma'k'eit particularly" adaptedl to the purposefofthe present invention.". Inl-claiming mercury evapor, it f is in*-`tended 'to' include any substance `that may be,iin fact, an equivalent;`These character- 15=istics principal-'lylare-r (l) :its boiling` points,

at practicable f absolute' pressures, correvsp'ond tol temperaturesdesirable in voil distillation ;=('2) vitmaybefbroughtas a vapor intoheat 'exchange relation' wvithr thev oil and, by

^ gumregulating the pressure, `may be caused to" condense at Ithe'temperature desired and-impart its latent heat tothe oil; 1(3) theamount of heattransfcrrableyto the' oilwith `each= degree of 'f.t'emperature 'diierence between ggs'the` mercury vapor and the oil is.gvastly greaterl thanwhere'ahotgas, Such as steam or vfurnace 1' gases-jis'v used' as,y a `heatingfmedi-` um (4) nearly all l' its heat isvlusefully ex,- pen'dedfin heat-ing the oil;'-' 5) avoidance of,

-:aolocal overhcatingfdue 'to 'high temperature differences between theheating medium and the oil; (6) economy' inthe amount rof "th'e heatingmedium required to vap'orize a given amount of oil, therebymaki'ngFitpracticable to avoidl the usefof an apparatus o f hugedi- A commerciallypracticable mercury lvapor distilling apparatus is shown in Fig. 3,wh1chis set forthjin detailin1-applications for pat ents filed by Pew andThomas-May 24, 1926, Serial Nos. 112,4431and112,444, `which matured intoPatents 1,714,811 and 1,714,812 respectively'on Mayv;28,"1929. rFrom-.amer- .cury boiler'geXtends a'mercuryvapor line rh'h'aving branchesextending-to the mercury chambers "m ofthe several vapori'zers l11, 12,13, etci, -each` of-which branch pipes is equipped/with avalve "i,by-means ofwhich therate .of flow of the mercury vapor intoy the mercuryvapor chamber of any vaporizer and `hencethe-pressurev within the samean the temperature of condensation within the same and tluaheat-towhich'the oil in such vaporizer is subjected,v may -be' independentv1y'regulated' "Extending from the mercury chamber 'of each vaporizeris 'amercury condensatereturn, which comprises pipe j, cup f lc, goose-neckm, pipe n and vesselo communicating with boiler y. shown areadapted notonly to allowmercury condensate to return to the boiler but to-pro-=vide balancing' columns of liquid mercury, to take care of'pfressuredifferences betweenthe boiler and the -mercuryw'apor chamber 6570i eachvaporizerr If desired, a-plurality them at di The connections ofboilers, operating .under dierentpres- 'j sures, may be employed fordifferent sets ofv vapor1zers, but it is still desirable to utilize thedescribed means for maintaining di'erenti-al kpressures in the boilerandin the mer;v cury vapor chambers of 4the. va-porizers lin order toavoid unnecessary high temperatures of `condensation inl the mercuryvapor cham\ bers ofthe vaporizers of the set inl which the rlighterfractions of the oil are driven olf.y From the mercury vaporsupply line hextends a pipe p communicating-.with a pres'- sure controlvalve -r which opens when the.`

lboiler pressurevexceed's `the desired maximum a-nd allows mercury vaporto `iovapast the tvalve into a Acondenser s which,through a goose-neck.pipe t, communicates-with Athe boiler g either directly or throughtheamercurycondensateline n. f. f i .j

lEach vaporizerl 11, 1-2, 13,`14,1 etc, comprises alongtubularcontainer, lpreterably oval in .cross-section and divided,by-means of apan or partition wfrunningglengthw'isethere-,j through,intofa mercury vaporvcondensing chamber a: and an oil vaporizing.chamben y. The-oil flows onto andy downoverthe pan w ofA eachvaporizer. in a comparatively thi-n stream and at a rapidrate,aminor-ractionv of the oil being vaporized in .each vaporizer 1f,as is preferable, a separatefvaporizer is. provided for each' desireddistillate. A single very long vaporizer may be substituted andprog'resslvelyv heavier vapors may betaken. olf 'separately alongthelength ofthe'vaporlzer and separately condensed; or vapors-may' betaken olf at different points along the length of a vaporizer andfractionally condensed; but, as above stated, it isfpreferabley toVprovide one vaporizer for each distillate,

t thereby permitting a minimum effective temsirable to provide apluralit of exitpipes v from vthe vaporizer, prefera 1y a number oferent parts along the; length, thereof, as shown in Fig. 2. v f

` The arrangement is suchthat no heaty isy applied to they vapors afterthey. leave the sur-i face of the oil; .no heat, in fact, beingdirectlyT applied to any part of the oil except the film l: thereof thatis, at anyv given moment, inconf' tact with the pan or partition w. Thetem" perature of the vapors, as they leave-'any' vaporizing chamber '1,is, infact, verymuchbelow the temperature of "any liquid oil withinthe'vaporizer'.

Gonnectedwi'th' the oil vapori'zing' cliamflv ber of each vapori'zeris ac'onde11sing,fre, luxing and deodorizin'g apparatus, Each, apparatusislike lthe others, vso that a de'-l scription of one will ysu'ilicelfor vall. y 4Suchsuch vaporizer. It is,- however, highlyde'- particleeff.

apparatus lforms the subject-matter vof applik escapes through pipes 'vto a header 18 and thence through pipes 19 to the lower part of a tower20 (see Figs. 1, 2 and 4). Just above the discharge mouths of pipes 19,and not'far above the bottom of the tower, is a grid`21, which supportsa pile of chemical tiles, preferably the well known Raschig rings, 22.Above and spaced from the top of the pipe of tiles 22 is another grid23, similar to grid 2l. Grid 23 supports another and higher pile oftiles 24, which may be of the same character as tiles 22.

Below grid 23 and above tiles 22, and spaced from both, is a pan orpartition 25 provided with an upstanding fiange 26 enclosing a centralvapor passage. Secured to the bottom of grid 23 is a defiector 27, whichconsists of an imperforate disc having a peripheral downwardly andobliquely extending flange whose periphery overhangs the annular spaceoutside of the fiange 26 of partition 25. f

The bottom of the tower communicates, through a pipe 28, with one of thevaporizers, preferably the same vaporizer as that from which the vaporspassed into the bottom o 'r' the tower, and with that end of suchvaporizer int-o which the main stream of oil is fed. The top of thetower communicates, through a pipe 29, with a stink oil receiver 35, towhich is connected a pipe 36 connected with'vacuum.

Any vapors carried into the'tower 20 from pipes-c that are heavier thanthe fraction cooled and most o't' them condensed.

'which it is desired to segregate will condense while going through thetiles' 22 and flow down to the bottom of the tower. Any particles of oilthat may possibly be entrained with the vapors will also flow to thebottom of the tower. Theirce the condensate, or condensate andunvaporized oil, will return to the vaporizer through pipe 28 and jointhe ingoing stream of oil.

The uncondensed vapors will passl up through the central opening in pan25, through the annular space around deflector 27 and through grid 23,and through thc high pile of tiles 24, wherein the vapors are Theuncondensablc gases escape through stink pipe 29 into the receiver 35.The condensate flows back through the tiles 24 and through the grid 23into the annular oil receiving pan 25. Thence the condensate passesthrough a pipe 30(having a goose-neck providing a trap 31,) into what Icall a deodorizer 40.

The distillate entering the deodorizer is in `fairly good2 condition,but it carries with it some products that impart a somewhat uudesirableodor to the oil and from which the oil should be freed.

The deodorizer 40 consists of an upright of outlet pipes 42, positionedrespectively.

The outlet pipes between adjacent plates 41. 42 are connected to aheader 43, which is connected, through a valved pipe 44, to a vacuumpump (not shown). The bottom of chamber 40 is connected, through pi e49. with a receiver 50, which is connect through a pipe 51, with asource of vacuum. The `odoriferous gases are removed from the oil oneach plate 41 and withdrawn from the receiver through pipes 42; theoperation being such that there can be no reabsorption of gases in theoil. The oil passing into receiver 50 Vis ready for the market withoutfurther treatment.

It should be stated, at this point, that by reason of the conditionsunder which the oil is vaporized, the va ors that enter most of thetowers 20 are wliolly devoid of cracked products, although, possibly, inthe latest'.

able odor to the oil. These products are believed to be fixed gases andaromatic gaseous compounds present in the crude oil; or they maybeproduced in the gasoline and gas oil topping operations preparatory tofeeding the oil tothe first vaporizer 11 of the series, especially ifthe hereinbefore described topping process is not used. It is also quitepossible that in all the vaporizers, as well as in the initial toppingoperations, there may be formed products produced by the breaking downof sulfur compounds. Whatever the character of the products may be thatimpart an undesirable odor to the lubricants distilled byv the presentprocess, they are mainly,4 and probably wholly, in gasphase. This isespecially true of the fractional distillates that go to the deodorizers40.

The operation in towers 2O and deodorizers 4() whereby theseodor-producing gases are removed is in no sense a distilling operation;that is, neither the tower 2O nor the deodorizer 40 is a still. Theoperation of distilling involves the conversation of liquid to vapor,which operation is believed not to occur either in the towers or in thedeodorizers. The conditions necessary' for vaporization are not presentin either; because, while there is a slight rise in vacuum, there is, atthe sameA enter the tower.

and a slight drop in heat inv the deodorizers. The distillate leavingthe towers at 30 may be at a teniperature from 150 to 200 F. lower thanthat of the vapors that enter the tower. What occurs in the towers isa-separation of gases from oil vapors and from liquid oil. Whatoccurs inthe deodorizers ris the further separation ofgasesfrom liquid oil. Theseparation in the towers is not complete, because the separated gasesare being continually reabsorbed by downlowing condensate. Theseparation in the deodorizers is practically perfect, because noopportunity is al'orded for reabsorption of released gases.

The percentage of' these odor-producing gases is. -very small even inthe vapors that The percentage of such gases in the distillate that Howsont the tower to the deodorizer is much smaller. In fact, due to thehigh vacuum to which the distillate is subjected, its gas content must,of necessity, be extremely low. An extremely small proportion ofodor-producing gases', however, suliices to impart a quite perceptibleodor to the oil. By distributing the oil in thin films over plates 41and agitating the 'films by maintaining them Iin motion along'the platesand dropping them from one plate to another, every particle of li uid isexposed to 'an extremely high vacuum say about 3 mm.

mercury absolute pressure) under which conditions, although novaporization may occur, no gas can remain in the oil. the oil isentirely deprived of the products that impart to it a disagreeable odor.

If a narrow range cut isl not desired, the Whole product maybe condensedand passed direct to the deodorizer 40. Whether or not the-heavierconstituents are reiluxed and returned to .the flowingstream of oil, thediss Y tillate need not be passed direct to the. deodorizer 40, butmaybe temporarily stored and subsequentlyfed to thedeodorizer at a regu:lated rate. y j The highest degree ofva'cuin, which ina be equal to anabsoluatepressurerof (say one to five millimetres mercury, is that'oper'- ative on the deodorizer 40, tank e, and receivers and 50, andparticularly the de-l odorizer. Without objectionably large con-vnecting pipes, there is some drop in the vacnum between the vacuumpumpsand the oil vaporizing chambers of the vaporizers, particularly if arefluxing and condensing tower 2O is used; ybut it isquite possible, ifthe pressure in the parts of the apparatus directly connected with thepump is no higher than 7 mm. mercury absolute, to maintain a pressurewithin the oil vaporizing chambers of the vaporizers below, and evenconsiderably below, 25 mm. mercury absolute.

The vaporizers need not be of any particular size, but vaporizers each20 feet long, 5 feet high and 21/2 feet wide, are practicable.

Consequently,

The vaporizersl areisol inclined astok have a fall of about one foot inJ34" feet.

The temperature of tlieoil entering the first e vaporizer ofthe seriesmay be (say) 410 F. and that of the oil entering the last va poirizerofthe series may be (say) 710 F. These iignres are illustrative merely.The ielati\'c-;

ly high temperature in the last vaporizer oi the series is substantiallylower than that re-k quired to vaporize the heaviest constituents Y thatare vaporizable in any ordinary `distilling process. In fact, the oil,by iny process, is capable of being distilled down to asphalt or coke,thereby producing new"lubricantsV having characteristics heretoforeunknown.

` Theoil may be admitted tot-he first vii-* porizer of the series at.the rate oi' 'onehunL v .y

died barrels (4200 gallonsfpcr hour. `rI he oil will occupy (say) yabout5.9 secondsfin'/y traversing the chambcrf'froin'pnc end ttli-ejfsother.' The velocity of flo'wwill be 'abontfll feet per second andtheaverage del'itl'ion the pan will be about 13-60th'of ani'nch.` About "itwelve per cent., or twclvebarrels perhour,

will be vapoi'ized and passv to th'econdenser. The residual oil thatHows to the second vaporizer will have a temperature of say) 450 F. Thedata given are merely illustrative, I

and moreover are based 'on"theassiimption that ten or twelvevaporizershavingthe same heating surfaces comprise the series. They lgive` a-good idea of desirable conditions of operation in the firstvaporigzer of the series.

As the oil flows through successive vaporizers e and 1s deprived ofprogressively heavier constituents, it becomes more viscous and lessfree flowing. i The time occupied iny lflowiine;

through a'vaporizer, the velocity of'lovi/the depth of the oil stream,and the yieldv of disf.

` stilled oil, all tend to decrease as theoil flows crease, at least lsofar -ascon'cerns .allgiz'iic tors, 1s not necessarily constantorf progreThe vprocessfae'lafpted to the described j.; apparatus vis one embodyingall the factors required to establish an extremely high -lvacuum onevery particleof the` oil being vaporized, as welllas all theviactorsVre quired to avoid conditions tending-to neutrali'ze or impairthe'advantages of By utilizing the latenthe'at of mercury vaporliberated'by its condensation', to heat 120 i. '1"mi through successivevaporizers; but such def' v which the desired'fraction of the oilvaporizers that yloca-l overheating is impossible. The desirable depthof the oil body in any vaporizer is such that the hydrostatic pressureon 4such of the oil particles as are in actual contact with the an orpartition of the vaporizer is negligib e. Indeed, while the stream ofoil is necessarily thin, it may be Substantiall thicker than thefraction of an winch herein forespecifedwithout producing a h drostaticpressure at the base of the co umnfthat would materially lower thevacuum.

No heat is directly Iap lied to any part of Ithe oilexceptthat w ich istransmitted through the pan along which the oil flows. Hence the'`.vapors themselves are not subjectedl'to heat.l This. feature is of theutmost.

importanoe,because there is abundant reava r phase., Hence,ifthe'temperature be suitably controlled,"'the'bottom of theoil filmmaybe subjected toa temperaturel within a.

through which oil and oil vapors were iow-A ing; although, erhaps, itwould be possible to so practice t e process in the distillation ofthelighter cuts. It would be quite feasible, however, to allow the oilto drop down over tubes through which mercury vapor is flowing and -inwhich it is condensed. The heat` ing, however, by means of furnacegases, Whose heat conductivity is relatively very low, is impracticable,even if an absolute vacuumv could be maintained in the tubes; because,in order to secure adequate heat transfer, either the temperature of thegases would have to be prohibitively high, or the total area of theheating surfaceswould have to be so great as to involve the use of anapparatus of impracticable size.

The present process also embodies the im-A portant features of controlof the temperav ture-of the heating medium at its locus of heattransfer, thereby 'avoiding the use of a vhigher temperature than isrequired to drive ofi'ja"predetermined fraction of oil. This factorisofY importance in the distillation of those heavier fractions wherein arelatively high .temperatureof condensation of the 1nercury vapor isnecessary, but wherein such temperature should-'he no Yhigher than isnecessary.

The present process also provides for extremely rapid and`directWithdrawal of the oil vapors from `the vaporizer, thereby notonly avoiding the continued'application of heat'thereto, but avoidingalso the building son n,to :believe that cracking .occurs onlyinl nlp ofpressure that would occur if, before ir escape, they were requiredtotravel vfor a substantial distance through a passage vof restrictedcross-sectional area along ywith the flowing bod of oil.

It should e understood that in the distillation-of thelightestfractionsof the oil a high vacuum is not essential, owing.l to the factthat the boiling points of the vapors need not exceed a crackingtemperature even with 7 a low vacuum, or possibly vevenv with no vacuum.Itis also true that in the distillation of the lightest fractions it is'of no special utility to provide for ,the condensation of the mercuryvapor at the lowest temperature that is effective to distil suchfractions, inasmuch as a somewhat higher temperature may not be an'effective cracking temperature. All the factors characterizingthe-preferred embodiment of the present process are required onlyin thedistillation of relatively high boiling point fractions. In distillingsuch fractions, not only should the pressure be maintained below'about25 mm. absolute but the difference between the temperature of vthe oilas it enters the space in which it is vaporized and the temperature yatwhich the mercury vapor is condensed should not exceed about iiftydegreesF.' The application of the process to the distillation of theheaviest 95 fraction of the oill produces distillatesgthat heretoforehave never ybeen producedvgat'` all, because byno other processlfis'f't.possible to drive themoi without overheating to such an extent that theyare decomposed into lighter viscosity products-and obviously nosubsequent re-distillations and chemical' treatments can convert suchproducts into high viscous lubricants. i v As hereinbefore stated, ifthe vapors leaving someor all of the vaporizers are condensed withoutany treatment at all, they have a somewhat objectionable odor which, Ywhile not affecting their lubricatingjproperties, may somewhat affecttheirv marketabilun ity. It may be said, however, that, after theremoval, in the last stage ofthe present proc# ess, `ofthe odorproducing gases, if a very small4 prcentage of a distillate like thatproduced ,ordinary processes b e` added to the oil pro ucedvby the,present process, it produces any odor more objectionable thanfthatwhich characterizes the oil that,- in the present process, isproducedvbymere distillation. Itis, therefore, clear'that, in thepresent process, the proportion of odor produring'products is very low.It seems probable, also, that they are composed, to a considerabledegree, if not solely, of fixed gases and aromatic compounds present inthe crude, or produced in the topping` or of broken down sulfurcompounds that break down at a low temperature, because they are presentto as great a degree, if not in a greater degree, in the lowest boilingdistillates proumi duced by the present process (which are not subjectedto any temperature that could po ssibly produce cracking) as in the highboiling distillatcs. At any rate, they1 are products which are removedlargely in the condensing process and completely in the specialdeodorizing process that constitutes the last step of the process; andsuch removal is effected as an integral part of the distilling processitself without any expense other than a capital expenditurel that doesnot much exceed the cost of ordinary condensers.

It is also entirely practicable, in myprocess, to inject steam into theoil and thereby reduce its boiling point, as is well known in the art.Such use of steam, however, discolors the final products unless thesteam be produced from water that has been thor- Vouglily deaerated. asdescribed in the patent issued to me April 2, 1929,- No. 1,707,448.

It should be understood that While in certain claims I have claimed, asapart of the process, the preparation of the crude oil for distillationof lubricating Jfractions by subjecting it to certain treatments, it isnot thereby intended to exclude the preliminary understood that thehighest grade lubricatdistillationof the lightest fractions by anymethod and the preparation of the residual oil for distillation oflubricating fractions by subjecting it to said treatments; the termcrude oil being intended to include any oil which is in aI crude staterelatively to the residual oil which is adapted for distillation oflubricating fractions.

lVhe're it is stated that the oil stream, 1n its progress through theapparatus, 1s confined against access of oxygen, it should be understoodthat it is intended to substantially exclude'the admission of oxygen insuch form, asl by admission of air, as would cause the oxygen to combinewith constituents of the oil and form objectionable oxidation products.l

The entire process, starting with the crude oil and ending with theultimate residue, 1s a continuous one and may be conducted 1n the singleapparatus described. The vnecessary successive distillations, as well asthe soda treatment-and subsequent dehydration, are` all so conducted,under such conditions of minimum temperature and controlled pressure,with exclusion of access of oxygen, as to prevent, or reduce to thelowest possible extent, the formation of cracked and oxidation productsand to neutralize, to the greatest possibleextent, any such productsthat may exist in the crude or be produced during the process. Finally,there are removed from the oil odor-producing gases that, whatever theirorigin may be, are contained in the distillates from the lubricating oilstills.

From the foregoing description it will be ing oil distillates cannot beproduced by a perfect process of lubrlcatlng oil distillation unless thedistillations and treatments to which the crude oil is subjected are ofsuch character as to provide a lubricating stock of proper qualit-y. Itwill also be understood that high grade lubricating oil distillatescannot be produced from perfect lubricating stock unless the lubricatingoil distillation process is so conducted as to prevent or minimize theformation of cracked and oxidation products that it is desired toexclude from the ultimate distillates. ,lt will also be understood thatperfect processes of preparing' lubricating stock and distillinglubricating oils cannot effect the removal of certain odor-producing andcolor-deteriorating products contained in the crude oil or produced bythe breaking down of sulfur compounds. The various steps of the completeprocess embodying this invention are, therefore, all interrelated. Thisinterdependence of the various steps of the ent-ire proccss may be madestill more clear by the statement that the various operations precedingthe lubricating oil distillation present no substantial advantage overknown opera. tions so far as concerns the production of gasoline, gasoil and other relatively low boiling constituents, but are practicedsolely for the purpose of producing a lubricating stock from which it ispossible to make the highest grade lubricating oils. These operationsare therefore a part of, or necessarily preliminary to, the process ofmanufacturing lubricating oil distillates.

That part of the herein described process which comprises the productionofv a lubricating oil stock substantially free of all impurities exceptcertain odor-producing and color-deteriorating products, namely, thatpart of the process which is herein described as being practiced in theapparatus shown in Fig. 5A and in that part of Fig. 5B preceding theintroduction of the oil to the first vaporizer of the lubricating oildistillation plant, is not herein claimed per se, but forms thesubject-matter of an application filed December 22, 1926, Serial No.156,287, which shows and describes the same apparatus and process, andof an application filed February 28, 1928, Serial No. 257,559, whichshows and describes an embodiment of the same apparatus and process inanimproved form.

N or'do I claim herein certain features of the within described processinvolving, inter alia, the vaporization of the oil by means of mercuryvapor and which may be carried out in lthat part of the lubricating oildistillation unit illustrated in Fig. 3 certain fea- -tures lof thispart of the herein described process forming the subject-matter of anapplication tiled by Pew and Thomas March 5,A 1925, Serial No, 13,040.

That part of the herein described process which comprises subjectingoil, from which al1 constituents, except odor-producing gases of lowerboiling point than that of the desired lubricating oil have beenremoved, to such heat and low sub-atmospheric pressure as will vaporizethe desired hydrocarbons without cracking, followed by subjecting themixed vapors and gases to reflux condensation under a somewhat lowersub-atmospheric pressure but also at such reduced temperature as toprevent further vaporization and effect condensation of substantiallyall the vapors except odor-producing gases, which condensate andseparated gases are separately removed, is not herein claimed per se,the saine forming the subject-matter of i a division hereof filed Feb.28, 1930, Serial No. 432,085.

Having now fully described my invention, what I claim and desire toprotect by Letters Patent is:

1. The process of producing lubricating oil distillates from crude oilwhich comprises preliminarily heating the oil and settling out water andsediment, flowing the oil in a continuous stream of restricted crosssection while heating the oil sufficiently to vaporize relatively lowboiling oil fractions but not sufliciently to producesubstantialcracking, separating and condensing oil vapors, establishinga flowing stream of hot residual oil, intimately mixing therewith asolution of an acid-neutralizing material, distributing the mixture o'foil and solution over an extended` surface and without substantialapplication of heat evaporating the solvent of the acid neutralizer,distributing the solvent-free oil over an extended surface whilesubjecting it to a' vacuum sufficiently high, without the application ofheat, to vaporize relative higher boiling oil fractions,.lowing a streamof residual oil through, rand distributing it over an extended surfacewithin, a confined space, flowing mercury vapor into heat exchangerelation with the oil so distributed and flowing over said surface, solimiting thete'mperature of the mercury vapor and the absolute pressureon the oi as to effect, by heat exchange and condensation of mercuryvapor, the vapox-ization of oil while minimizing cracking, subjectingthe oil vapors in a distributed condition to reflux condensation andunder a vacuum suflicient to extract therefrom odor-producing gases,flowing' oil so condensed 1n a shallow, turbulent stream overa series ofextended surfaces within a confined space, and,

without substantial distillation of its liquid c of fent's, subjectingthe oil to a vacuum sii cient to remove from the oil odor-producinggases, and preventing reabsorption of the gases from the oil byimmediately withdrawing thegases from the confined space, and

substantially excluding access of oxygen to the oil during the specifiedtreatments.

2. The process of distilling lubricating oil which comprises flowing astream of oil continuously into, through and out of a confined space andwhile passing through said space distributing the oil over, andmaintaining the progresswe travel of the oil over, a surface adapted tobe heated, generating mercury vapor from a body of liquid mercury andfiowing such vapor into heat exchange relation, but out of contact, withthe oil that is so distributed and flowing over said surface, and

effecting, by heat exchange and condensation of mercury vapor,-thevaporization of oil,` maintaining all parts of the oil flowing throughsaid space under an absolute pressure substantially less than 25millimeters mercury, and condensing the mercury vapor as above specifiedat a temperature not over about 50 degrees F. in excess of thetemperaturc of the oil entering said space, thereby eecting thedistillation of relatively heavy fractions of the oil at temperatures solow that cracking is substantially prevented.

3. The process of producing lubricating oil distillates free fromodor-producing gases which comprises subjecting liquid oil to thermalconditions adapted to produce condensible oil vapors containingodor-producing gases, removing the oil vapors and condensing them,anddistributing condensate over an. cxtendedarea and while sodistributed subjecting it to a vacuum sufficiently high to removetherefrom odor-producing gases.

4. The process of producing lubricatingoil distillates free from`odor-producing gases which .comprises subjecting liquid oil to thermalconditions adapted to producecondensible oil .vapors containingodor-producing gases, removing the oil vapors and condensing them,flowing condensate in a shallow, turbulent stream over a series ofextended surfaces within a confined space, and, without substantialdistillation, subjecting the oil to a Vacuum sufciently high to remove4odorproducing gases, and 'preventing reabsorption of the gases by theoil by immediately withdrawingV the gases from the confined ace' l Y .vThe'process"of'producing lubricating oil ydistillates free from.odorreducing gases which comprises subjecting liquid oil to thermalconditions adapted to 'produce condensible oil vapors containinglodor-producing gases, subjecting the oil vapors to reflux condensationand slmultaneously therewith, un-

dev` a high vacuum, effecting a artial removal of odor-producing gases,and owing condensatefrom whichl the odor-producin gases A' have beenpartly removed over exten ed surfaces while under a vacuum sullicientlyhighv to extract substantially `all the remaining Aodor-producinggases', and immediately removing extracted'` gases from the region ofthe flowing stream to prevent their reabsorption.

6. The process of producing lubricating oil distillates free fromodor-producing gases which comprises subjecting liquid oil to thermalconditions adapted to produce lthe condensate from which such gases havebeen partly removed over extended surfaces while under-a vacuumsufiiciently high to extract substantially the remainder of such gasesand simultaneously removing the extracted gases fronr the region of theflowing stream to preventl their reabsorption.

7. The process of distilling lubricating oil which comprises flowing astream of' oil continuously into, through and out of a confined spaceand while passing the oil through such space distributing it over asurface adapted to be heated, generating mercury vapor from a body ofliquid'mercury and flowing such vapor into heat exchange relation, butout of contact, with the oil that'is so distributed and flowing oversaid surface, maintaining such temperature of the mer'- cury vapor as toeffect, by heat exchange and condensation of mercury vapor, thevaporization of oil, removing the oil vapors and condensing them, anddistributing condensate over an extended area and while so distributedsubjecting it to a vacuum sufficiently high to remove therefromodor-producing gases.

8. The process of distilling lubricating oil which comprises flowing astream of oil conu tinuously into, through and out of a confined spaceand While passing the oil through such space distributing it over avsurface adapted to'be heated, generating mercury vapor from a body ofliquid mercury and flowing such vaporinto heat exchange relation, butout of contact, with the oil that is so distributed and flowing oversaid surface, maintaining such temperature of the mercury vapor as toeffect, by heat exchange and condensation of mercury vapor,thevaporization of oil, removing the oil vapors and condensing them,flowing condensate in a shallow, turbulent stream over a series ofextended sur- 'faces within a confined space, and, without .substantialdistillation, subjecting'the'oil to a vacuum sufficiently high to removeodorproducing gases, and preventing reobsorption of the gases by the oilby immediately withdrawing the gases from the confined space.

9. The process of distilling lubricating oil which comprises flowing astream of oil continuously into, through and out of a confined space andWhile passing the oil through such space distributing it over a surfaceadaptedd to be heated, generating mercury vapor from a,bodv of liquidmercury and flowing asuch vapor into heat exchange relation, but out ofcontact, with the oil that is so distributed and flowing over saidsurface, maintaining 'such temperature of the mercury vapor as toeffeet, by heat exchange and condensation of mercury vapor, thevaporization of oil, eT- fecting a partial removal of odor-producinggases, and flowing condensate from which the odor-producing gases havebeen partly removed over extended surfaces while under a vacuumsufficiently high to extract substantially all the remainingodor-producing gases, and immediately removing extracted gases from theregion ofthe flowing stream to prevent their reabsorption.

l0. The process of distilling lubricating oil which comprises flowing astream of oil continuously into, through and out of a confined space andwhile passing the oil through such space distributing it over a surfaceadapted to be heated, generating mercury vapor from a body of liquidmercury and flowmg such vapor into heat exchange relation,

but out of contact, with the oil that is so distributed and flowing oversaid surface, maintaining such temperature of the mercury vapor as toeffect, by heat exchange and condensation of mercury vapor, theVaporization of oil, subjecting the oil vapors to fractional refluxcondensation, returning the heavier condensate to thestream of oilundergoing vaporization, and subjecting th'e lighter condensate, whilein a distributed condition, Without substantial distillation, to avacuum sufficiently high to remove therefrom odorproducing gases.

11. The process of distilling lubricating oil which comprises flowing astream of oil continuously into, through and out of a confined space andwhile passing the oil through such space distributing it over a surfaceadapted to -be heated, generating' mercury lvapor from a body of liquidmercury and flowing such vapor into heat exchange relai tion. but out ofcontact, with the oil ythat is so distributed and flowing over .saidsurf I face, .maintaining such temperature 'of the mercury vapor 4as toeffect, by heat exchange and condensation of mercury vapor, thevaporization of oil, subjecting the oil vapors to fractional refluxcondensation, returning the heavier condensate to the steam ofV oilundergoing vaporization, and simultaneously with the condensation ofthe'lighter'condensate, and under a high vacuum, effecting a partial-removal of odorfproducing gases, and flowing the condensate from whichsuch gases have been partly removed over extended surfaces lwhilender a,vacuum sufficiently high to extr/act substantially the remainder of suchgases and simultaneously removing extracted gases from the region of theflowing stream to prevent their reabsorption.

12. The process of distilling lubricating oil which comprises flowing astream of oil continuously into, through and out of a confined space andwhile passing the oilthrough such lan absolute pressure of substantiallyless than 25 millimeters mercury upon the oil stream, oil vapors andcondensate, thereby enabling relatively high boiling fractions to bedistilled at temperatures so low that cracking is avoided or minimizedand enabling odor-producing gases to be removed without substantialdistillation.

13. The process of producing lubricating oil distillates from crude oilwhich comprises: first, preparing lubricating stock by subjecting theoil to conditions of heat and pressure adapted to vaporize lighterfractions while confining the oil against access of oxygen to therebyavoid any substantial production of oxidation products and therebyvaporizing such lighter fractions, and withdrawing the vapors 3 second,while continuing to confine the oil against access of oxygen, subjectingthe residual lubricating stock thus produced to conditions of heat andpressure adapted to vaporize lubricating oil fractions and therebyproducing condensible lubricating oil vapors containing odor-producinggases; and third, While continuing to confine the oil against access ofoxygen, condensing lubricating oil vapors containing such gases anddistributing the condensate over an extended surface at a locus removedfrom the locus of vaporization and while so distributed subjecting it toa high vacuum and thereby, without substantial distillation, removingodor-producing gases.

14. The process of producing lubricating oil distillates from crude oilwhich comprises: first, preparing lubricating stock by subjecting theoil to conditions of heat and pressure ada .t'd to vaporize lighterfractions while con ming the oil against access of oxygen to therebyavoid any substantial production of oxidation products and therebyvaporizing such lighter fractions, and withdrawing the vapors'tandsecond, flowing a stream of the residual lubricating stock thus producedcontinuously into, through and out of a confined space also confinedagainst access of oxygen and while passing through said spacedistributing the oil over, and maintaining the progressive travel of theoil over, a surface adapted to be heated, generating mercury vapor froma body of mercury and flowing such vapor intoheat exchangerelation,butout of Contact, with the oil that is so distributed andflowing over said surface, maintaining such limited temperature of themercury vapor and such limited absolute pressure on the oil as toeffect, by heat exchange and condensation of mercury vapor, thevapor-ization of the oil while minimizing cracking, and removing the oilvapors and condensing them.

15. The process of producing lubricating oil from crude oil whichcomprises: first, preparing lubricating oil stock by subjecting the oilto conditions of heat and absolute pressure adapted to vaporize lighterfractions without substantial cracking and thereby vaporizing suchlighter fractions and withdrawing the vapors; second, subjecting theresidual lubricating stock thus produced to conditions of heat andabsolute pressure adapted to minimize cracking and vaporize lubricatingoil fractions and thereby producv ing condensible lubricating oil vaporsapproximately free from cracked products but containing odor producinggases; and third, condensing lubricatinof oil vapors containing suchgases and distri uting the condensate over an extended surface at alocus removed from the locus of vaporization and while so distributedsubjecting it to a high vacuum and thereby, without substantialdistillation, removing odor-producing gases and throughout the processconfining the oil and oil vapors against any substantial access ofoxygen adapted toieffect substantial production of oxidation products.

16. The process of producing lubricating oil from crude oil whichcomprises: first, preparing lubricating oil stock by subjecting the oilto conditions of heat and absolute pressure adapted to vaporizecondensible lighter fractions without substantial cracking and -therebyvaporizing such fractions, and withdrawing the vapors; and second,flowing a stream ofthe lubricating stock so produced continuously into,through and out of a conlined space and while passing through said spacedistributing the o il over, and maintaining the progressive travel ofthe oil over, a surface adapted to be heated, generating mercury vaporfrom a body of mercury and flowing such vapor into heat exchangerelation, but out of contact, with the oil that is so distributed andflowing over saidsurface, maintaining such limited temperature of themercury vapor and such limite'tlabsolute pressure on the oil as toelfectgjby heat exchange and condensation of *mercury vapor, thevaporization of the V`ajil while minimizing cracking, and remoging theoil vapors and l condensing them and throughout the process pressureadapted to vapoi-ize Alighter vfrac-` tions while substantially avoidingcrackin and while confining the oil againsty access o oxygen,whereby theproduction of cracked and oxidation products is substantially preventedand thereby ,vaporizing,A such frac- 'tions and withdrawing the vapors;second,

liis

subjecting the residual lubricating stock thus produced to conditions ofheat and pressure adapted to minimize cracking and' vaporize lubricatingoil fractions and thereby produc- -ing condensiblev .lubricatinproximately free from crac ed pro ucts but containing odor-producinggases while continuing to confine the oil against access of oxygen; andthird, condensing lubricating oil vapors vcontaining such gases anddistributing the condensate 'over an extended surface at a locus removedfrom the locus of vaporization and while so distributed subjecting it toa high vacuum and thereby, and without substantial distillation,removing odor-producing gases.

18. The process of producing lubricating oil distillates from crude oilwhich comprises: first, preparing lubricatin stock by sub]ect ing theoil to conditions o heat and absolute pressure adapted to vaporizelighter fr actions while substantially yavoiding 'cracking and whileconfining the voil against access of oxygen, and thereby vaporizing saidfractions and withdrawing the vapors, whereby the production of cracked.and oxidation products is substantially prevented; and second, flowing astream of the residual lubricatingstock thus producedcontinuously into,through and out of a confined space also confined against access ofoxygen and while passing through said space distributing the oil over,and maintaining the progressive travel of the oil over, a surfaceadapted-to be heated, generating mercury vapor from a body of mercuryand fiowing such vapor into h eat exchange relation, but out of contact,with the oil that is so distributed and fiowing over said surface,maintaining such limited temperature of the mercury vapor and suchlimited absolute pressure on the oil as to effect, by heat exchange andcondensation of mercury vapor, the vaporization of the oil whileminimizing cracking, and removing the oil vapors and .condensing them.

19. The process of producing lubricating oil distillates from crude oilwhich comprises: first, preparing lubricating stockby first heating theoil while it flows rapidly in a continuous stream of restrictedcross-section at a temperature sufiicientl high to effect vaporizationof relatively ower boiling constituents and sufiiciently-low to avoidsubstantial cracking, lremoving and condensing vapors, then distributingresidual oil over an extended surface while subjecting it to asubstantial vacuoil va ors apv `and sufficiently low to avoi t.cracking, removing and condensing vapors,v

umland'while continuing to so limit` the temperature as to avoidsubstantial cracking, rey moving and condensing vapors; second,submately free from cracked products but coni taining odor producingases and third, condensing lubricating oi vapors and distributing thecondensate over an extendedjsurface at a locus removed from the locus ofvaporization and while so distributed subjecting it to a high vacuum andthereby, withoutsubstantial distillation, removing odor-producing gasesand throughout the process v'confining the oil and' oil vapors against'any substantial access of oxyven adapted toeflect substantialproduction of oxidation products.

20. The process of producing vlubricating oil distillates from crude oilwhich comprises: first, preparing lubricating' stock by first heatingthe oil while it fl'ows rapidly in a continuous stream of restrictedcross-section at a temperature sufiiciently high to effect 'vaporizationof relativel lower boilin constituents and sufiicienti'y7 low to avoivapors, then distributing residual oil over an extended surface whilesubjecting to 'a substantial vacuum and while continuing to so limit thetemperature as vto avoid substanvvtial cracking, removing and condensingvapors; and second, flowing astream ofthe lubricating stock so 'producedcontinuously into, through and out of a confined space and while assingthrough said space distributing the oi over, and maintaining therogressive travel of the oil over, a surface a apted to be heated,generating mercury v'vapor from' a body of mercury and flowing suchvapor into heat exchan e relation, but' out of contact, with the oil tat is so distributed and flowing oversaid surface, maintaining suchlimited f' temperature of the mercury vapor and'such out the processconfining the oilA and oil vapors against any substantial access ofoxygen ada ted to effect substantial production of oxi ation products. v

21. The process of reducing lubricating oil distillates from cru eoilwhich comprises:

subv vstantial cracking, removing and ycondensing iio first, preparinglubricating oil stock by first heating t e oil, while it flows rapidlyin a continuous stream of restricted cross-section, at a temperaturesufficiently high to effect vaporization of relatively lower boilin oilfractions substantial then fiowing away residual hot oil and mixing itwith an acid-neutralizing solution and dis- Y.

v tributinr the oil over an extended area while it is subjected tosufficiently low absolute pressure yto va orize the solvent and alsorelatively higher oiling oil fractions and While contmuingto so limitthe temperature as to avoid substantial cracking, removing andcondensing vapors; second, subjecting the residual lubricating stockthus produced to conditions of heat and absolute pressure ada ted tominimize cracking and produce con ensible oil vapors approximately 'freefrom cracked products but containing odor roducing gases; and third,condensing lubricating oil vapors and distributing the cony densate overan extended surface at a locus removed from the locusof vaporization andlwhile so distributed subjecting it to a high vacuum and thereby,without substantial distillation, removing odor-producing gases andthroughout the process coniining the oil a-nd oil vapors against anysubstantial access of oxygen adapted to eiect substantial production ofoxidation products.

22. The process of producing lubricating oil distillates from crude oilwhich comprises: irst, preparing lubricating oil stock by first heatingthe oil, while it flows rapidly in a Agontinuous stream of restrictedcrosssection',v at a temperature suiciently high to effect vaporizationof relatively lower boiling oil fractions and suciently low to avoidsubstantial cracking, removing and condensing vapors, then iiowing awaresidual hotoil and mixing it with an aci neutralizing solution anddistributing the oil over an extended area while it is subjected tosufficiently low absolute pressure to vaporize the solvent and alsorelatlvely higher boiling oil fractions and while continuing to so limitthe temperature as to avoid substantial cracking, removing andcondensing vapors; and second, flowing a stream of the lubricating stockso produced continuously into, through and out of a confined s ace andwhile passing through said space istributing lthe oil over,l andmaintaining the progressive travel of theoil over, a surface adapted tobe heated, generating mercury vapor from a body of mercury and flowingit flows rapidly in a continuous stream of limited cross-section, at atemperature sufficiently high to edect vaporization of the relativelylower boiling oil fractions and sufficently low to avoid substantialcracking, removing and condensing vapors, then flowing away residual hotoil and mixing it with an acid-neutralizing solution, distributing theoil over an extended area and vaporizing off solvent while continuing toso limit the temperature as to avoid substantial cracking, and thendistributing the oil over an extended area vunder a reducedand'sub-atmospheric pressure and thereby vaporizing relatively higher-boiling oil fractions while continuing to so limit the temperature asto avoid substantial cracking, and removing and condensing vapors;second, subjecting the residual lubricating stock thus produced toconditions of heat and absolute pressure adapted to minimize crackingand produce condensible oil vapors approximately free from crackedproducts but containing odor producing gases; and third, condensinglubricating oil vapors and distributing the condensate over an extendedsurface at a locus removed from the locus of vaporization and while sodistributed subjecting it to a high vacuum and thereby, withoutsubstantial distillation, removing odor-producing gases and throughoutthe process confining the oil and oil vapors against any substantialaccess of oxygen adapted to effect substantial production .of oxidationproducts.

24. The process of producing lubricating o1l'which comprises: first,preparin lubrieating oil stock by first heating the oil, while 1t flowsrapidly in a continuous stream of limited cross-section, at atemperature suficiently high to effect va orization of the relativelylower boiling oil ractions and sufficiently low to avoid substantialcracking, removing and condensing vapors, then iiowing away residual hotoil and mixing it with an acid-neutralizing solution, distributing theoil over an extended area and vaporizing oil' solvent while continuingto so limit the temperature as to` avoid substantial cracking, and thendistributing the oil over an such vapor int heat exchangerelation,'butvextended area under a reduced and Suba@ out of contact,with the oil that is so distributed and iowing over said surface,maintaining such limited temperature of the mercury vapor and suchlimited absolute pressure on the oil as to effect, by heat exchange andcondensation of mercury vapor, the vaporization of the oil whileminimizing cracking, and removing the oil vapors and condensing them andthroughout the process confining the oil and oil vapors against anysubstantial access of oxygen adapted to eiect substantial production ofoxidation products.v

23. The process of producing lubricating oil which comprises: rst,preparing lubricating oil stock by first heating the oil, whilemospheric pressure and thereby vaporizing relatively higher boiling oilfractions while

